Hydraulic elevator



(No Model.)

S. E. STORES! Hydraulic Elevator. No. 243,649. Patented June 28,1881.

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UNITED STATES PATENT OFFICE- SAMUEL E. STOKES, OF PHILADELPHIA,PENNSYLVANIA.

' HYDRAULIC ELEV'ATOR.

SPECIFICATION forming part of Letters Patent No. 248,649, dated June 28,1881. Application tiled April 22, 1881. (No model.)

To all 'whom it may concern:

Be it known that I, SAMUEL E. SToKEs, a citizen of the United States,residing in Philadelphia, Pennsylvania, have invented certainImprovements in Hydraulic Elevators, of which the following is aspecification.

My invention relates to that class of hydraulic elevators in which avertical cylinder having a piston connected to the cage or car iscombined with appliances by which water under pressure can be admittedto the cylinder above the piston for hoisting, and to the cylinder belowthe piston for lowering the car; and the object of my invention is toreturn the water which has been used for lowering the piston and raisingthe carto the source of 'supply during the raising of the piston andlowering of the car, so that there shall be only one discharge throughthe waste-pipe of one cylinderful of water during one complete trip upand down of the ear,instead of two discharges.

In the accompanying drawings, Figure 1 is a side view, drawn to areduced scale, of my improved hydraulic elevator; Fig. 2, part of.

Fig. 1, drawn to an enlarged scale; and Figs.

3, 4, and 5, sections of the ch ange-valve in different positions.

In the vertical cylinder Gis a piston, H, the

rod or rods I of which are connected to the cark W through the medium ofdifferential drums, as shown, or through the usual block-and-fallmechanism, or any other available appliances, this part of the hoistingapparatus forming no part of my present invention.

Near the base of the cylinder is a chambered valve-chest, K, containingthe change-valve M, and this chest communicates through a pipe, C, withthe upper end of the cylinder above the piston, and through a pipe, D,with the cylinder below the piston. The chest also communicates, throughthe pipe A, with the tank N, through a pipe, B, with the same tank, andthrough a pipe, P, with the dischargechamber, the pipes A and Bextending nearly to the bottom of the tank. This tank is closed, and asupply of water under pressure is forced into it to make up for the lossexplained hereinafter; but there is always air in the tank above thewater, and under sufficient pressure to actuate the`piston of thecylinder, in the manner described hereinafter.- The tank is adopted incases where it is advisable to have the supply of water in the basementof a building, for an open tank, into which water is pumped, may beplaced in the upper part of the building at such an altitude as toobtain thedesired pressure bythe head of wateronly; 0r the supply may beobtained directly from city mains where there is a sufficient head ofwater.

It may be remarked here that I do not desire either to claim or restrictmyself to the valve and valve-chest illustrated in the drawings, as theresults attained thereby may be accomplished by other systems of valves,ports, and passages, the plan shown being given as an example and as anaid to the explanation ofthe mainprincjples and operations of myinvention.

We will suppose that the piston is approaching the limit of its downwardmovement, and that the car is approaching its highest'position, thevalve being as shown in Fig. 3, so

that there will be aclear passage for water under pressure from thetank, through the pipe A, valve and pipe C, to the top of the cylinder,this being the condition of affairs from the time the'piston commencedto descend and the oar t0 ascend, the Water below the cylinder meanwhileescaping through the pipe D, the valve-chest and valve, and out throughthe discharge or waste pipe P. When the piston has to belraised andthe-car lowered the valve is turned to the position Fig. Aet, when thereis such a change of passages that water under pressure from the tank Nwill pass through the pipe B, valve-chest, and pipe D to the cylinderbelow the piston, the outlet to the escapepipe being closed. At the sametime com munication is open between the cylinder at the top of the sameand the tank through the pipe C,

valve-chest and valve, and pipe A. Under P cylinder on both sides ofthepiston is the same, there must be a less pressure on the top of the IOOpiston, owing to the diminution of its area by the presence of thepiston rod or rods, than there is on the under side of the said piston,

and this excess of pressure from below assists the carin its descent.When the car has to be arrested at any point between the limits of itsupward and downward movement the valve must be entirely closed, as shownin Fig. 5, when the piston will be locked in the cylinder by and betweentwo bodies of water which cannot escape.

It will be seen wit-hout further description that while two cylindersfull of water are demanded by each round trip, up and down, of the ear,one cylinderful only is discharged through the waste-pipe, the othercylinderful being restored to the source of supply, and th at thisreturn of water involves no expenditure of power, for the reason thatduring the ascent of the piston and descent of the cage the pressure onboth sides of the piston is balanced.

Two sources of supply of waterone at a high pressure and the other at alower pressure-have been described in connection with a verticalcylinder, piston, and cage in a hydraulic elevator, the water for thelow-pressure supply bein gderived from the cylinder beneath the piston,while the high-pressure supply is depressing the piston and raising thecage. This plan differs, however, from my invention, in which there isbut one source of supply to which the water expended in depressing thepiston and raising the cage is returned to the said source oi' supply bythe cage during its descent.

I claim as my invention- 'Ihe combination, in a hydraulic elevator inwhich water is returned to the single source of supply, of the followingelements, namely: rst, a vertical vcylinder having a piston connected toa car or cage; second, means for obtaining a supply of Water underpressure for depressing the piston; third, a change valve or valves;fourth, pipes through which water from the cylinder above the piston maybe directed by the valve or valves to the said single source of supplyduring the descent of the car or cage, all substantially as set forth.

In -testimony whereof I have signed my name to this specification in thepresence of 5o two subscribing witnesses.

SAMUEL E. STOKES.

Vitnesses:

ARMEs F. MoCoRMrcK, HARRY SMITH.

